Recently, various materials are being developed for high integration and high performance of semiconductor devices. As the wiring materials in devices, aluminum and its alloys are used conventionally.
An aluminum wiring is formed by patterning with a photoresist on an aluminum membrane formed on an insulation membrane, etching, and then, peeling the masked photoresist. Therefore, on the surface of the aluminum wiring, there is significant adhesion of the photoresist not peeled, and there are the residue of the photoresist ashed by oxygen plasma and the like during etching, and gas components used in patterning and plasma treating, on the side surface of the aluminum wiring, bottom between the wiring and wiring, top of the wiring, and the like.
For removing these residues, there is disclosed a method of using an aqueous solution containing a quaternary ammonium hydroxide, and saccharides or sugar alcohol (JP 04-048633A).
On the other hand, a copper wiring is paid to attention as a wiring material in a device, for higher performance and higher speed treatment of a semiconductor device.
A copper wiring is formed by previously forming an insulation membrane having grooves, then, burying copper in the grooves by a plating method and the like, and polish-removing the copper membrane on parts other than the grooves by a chemical mechanical polishing method (hereinafter sometimes abbreviated as CMP) using a polishing agent containing grinding grains of silica, alumina or the like having a diameter of 1 μm or less and an additive for preventing corrosion of copper, and a polishing pad made of a material such as polyurethane and the like. Consequently, on the surface after formation of a copper wiring, there is significant adhesion of grinding grains of silica, alumina or the like in the polishing agent used for CMP, and fine polishing trashes of copper polished from the surface, on the surface of the buried copper wiring and on the insulation membrane.
Since it is also necessary that an insulation membrane is formed on the surface of the copper wiring, after a copper wiring is formed by CMP, and washing with washing liquid is conducted, there is a problem that an organic substance due to an additive contained in washing liquid remains and poor adherence occurs between the copper wiring and insulation membrane.
Therefore, there has been a desire for development of washing liquid capable of removing grinding grains of silica, alumina or the like in a polishing agent, and polishing trashes of copper, additionally, leaving little organic substance due to an additive used for preventing corrosion of copper on the surface of a copper wiring after washing, while corrosion of copper, which is corroded more easily than aluminum, is suppressed.